Little is known about this class which made it's appearance in "The Best of Both Worlds, Part II".
While on-screen, it was believed to look like a Constitution-class ship
with the nacelles attached to the saucer. Michael Okuda recently came out with a statement regarding
the "Wolf 359 ships" describing that the Challenger looked like a scaled-down
Galaxy-class saucer, hull with two nacelles, one above and one below the engineering hull.

The class was named in honor of the Earth spaceship that was destroyed in 1986 in which seven people
were killed.

USS Armstrong NCC-57537
Ambushed by a Klingon battle group in 2373 and took heavy damage; docked at
Deep Space-9 for medical aid.Named for Neil Armstrong, the first human to walk on Earth's moon.
"Apocalypse Rising" - DS9.

USS Buran NCC-57580
Destroyed by the Borg at Wolf 359 in 2367.Named for the Russian space shuttle, which also means "snowstorm."
"Best of Both Worlds" - TNG.

USS Challenger NCC-
Class prototype.

USS Kearsarge NCC-57566
Scheduled to rendezvous with the
USS Enterprise NCC-1701-D in 2370, however postponed.Named for the American aircraft carrier that recovered the Freedom Seven space craft.
"Firstborn" - TNG.